In industrial production, colloidal substances are used frequently. Because the colloidal substances are great in density and poor in fluidity, bubbles difficult to remove can be easily generated in the colloidal substances, and these bubbles cause bad influences on subsequent production.
For example, in a TFT-LCD manufacturing industry, if photoresist used for coating a colored thin film contains bubbles, then many problems happen to the colored thin film produced through the photoresist containing the bubbles in aspects of thickness, uniformity, optical density and the like, and therefore quality of a product is reduced, and a defect rate of the product is increased.
There are several bubble removing devices and methods in current industrial production, one is to remove bubbles according to a principle that the bubbles naturally float upwards in liquid, and the other is to remove bubbles according to a semipermeable membrane principle. But efficiency for removing bubbles in colloidal substances by these methods is low.
Thus, how to efficiently remove the bubbles in the colloidal substances becomes a technical problem urgently needing to be solved in the field.